The present invention relates to a set of equipment items for an aircraft comprising a video transducer and at least two head-up display devices—known as HUD devices—one of the HUD devices being intended for the pilot, the other HUD device being intended for the copilot of the aircraft. The invention also relates to an electronic compensation method making it possible, for each HUD device, to alleviate a discrepancy of conformity between a projected image formed from a video image captured by the video transducer and an external scene ahead of the aircraft.
It is known to use a video transducer to capture an image of the external environment ahead of an aircraft for the purpose of improving the perception of this environment by the pilot (“situation awareness”). The image delivered by the video transducer is projected focused at infinity by the HUD device—generally onto a transparent screen—in such a way that it is superposed on the external scene viewed by the pilot through this screen. Any offset between the projected image and the external scene or between the projected image and the symbology generated and projected onto the screen by the HUD device has the effect of hampering the pilot's perception instead of improving it.
According to the standards currently in force, the discrepancy of alignment between the line of sight of the HUD device, defined as being the axis passing through the theoretical eye of the pilot and the center of projection on the screen, and the line of sight of the video transducer, or in other words the optical axis of the said transducer, must not exceed 5 mrad. In addition, the resultant image projected by the HUD device and formed by the superposition of the video image transmitted by the video transducer and the symbology generated by the HUD device, must be in conformity with the external scene viewed by the pilot.